1. Field of Invention
The present invention relates to a scalable semiconductor memory device. More particularly, the present invention relates to a flash memory cell.
2. Description of Related Art
The split-gate flash memory is used in standalone and embedded nonvolatile memory because of the advantages of fast erase speed, high programming efficiency, and most important, no verification after program and erase. The erase is achieved through sharp poly tip by means of field-enhanced Fowler-Norheim (F-N) tunneling, and the program is accomplished by source-side hot carrier injection (SSI).
However, there are some problems for the conventional split-gate flash memory about the program disturb, such as the punch-through disturb, the reverse tunneling disturb, the row punch-through disturb or the like. The root cause of program-disturb is verified to relate to a large source voltage in the programming operation.
In view of the foregoing, there is a need in the related field to provide a new flash memory cell to prevent above-mentioned program disturb worse.